Certain types of printing systems are adapted for printing images on large-scale printing media, such as for museum displays, billboards, sails, bus boards, and banners. Some of these systems use so-called drop on demand ink jet printing. In these systems, a piezoelectric vibrator applies pressure to an ink reservoir of the printhead to force the ink out through the nozzle orifices positioned on the underside of the printheads. As a carriage which holds the set of print heads scans across the width of the print medium, the print heads deposit ink as the substrate moves. A particular image is created by controlling the order at which ink is ejected from the various nozzle orifices.
Some of these systems use inks with different colors to create the desired image. For instance, black, yellow, cyan, and magenta colored inks are commonly employed alone or in combination to generate the image. Thus combinations of these four base colors are used to create various other colors. For instance, a green region of the image is produced by depositing a yellow layer of ink and a cyan layer of ink. Typically, multiple print heads are used to deposit each color, and the print heads associated with each color are clustered together. Typically, the order of the layering of ink as the carriage moves in one direction is reversed as the carriage moves in the opposite direction.